1. Technical Field
The embodiments herein generally relate to pilot-based channel schemes, and, more particularly, to application of superfast algorithms to a pilot-based channel estimation process.
2. Description of the Related Art
In Orthogonal-Frequency-Division-Multiplexing (OFDM) systems, channel estimation is normally performed in the frequency domain, by dividing the received signal by a limited number of pilot coefficients within the OFDM block. The resulting set of coefficients are then interpolated which are often poor estimates, in order to approximately yield the full channel information in the frequency domain. The complexity of this procedure is O(M), where M is the Discrete Fourier Transform (DFT) size, in addition to the complexity of the interpolation method.
The practical use of any equalization scheme that relies on pilot based channel estimates is often hindered by computational requirements, especially in cases where a precise estimation criterion is crucial. Moreover, the quality of the first estimate will have a great impact on the complexity of subsequent channel estimates if a channel tap detection procedure is to be employed. Several methods are approached for the channel tap detection, all of which contain an initial least square (LS) estimator where the main burden is due to the inverse matrix which was not linked to any structural problem that can be solved in an efficient manner. Also, traditional methods estimate minimum mean-square-error (MMSE) or LS channel online and tend to have high complexity in computations and storage requirements.